At least 31 people were killed and dozens more were wounded when bombs went off in the airport and on a subway train in the Belgian capital, authorities said. The Islamic State group has claimed responsibility for the attacks.

TigerSwan, which was founded by former members of Delta Force, the Army’s elite tactical division, has hundreds of personal and corporate clients in dozens of countries, including Belgium.

“We have some (clients) that are unaccounted for right now, so obviously, we're personally devastated by it,” said Shawn Sweeney, a Special Operations veteran and TigerSwan’s vice president of operations.

Sweeney and other executives spent much of the day trying to track down their clients, many of whom have signed up for a tracking program that allows TigerSwan to keep tabs on them on a global map in the company’s operations center.

People’s best protection is situational awareness, he said, noting people need to look up from their smartphones and laptops from time to time to know what’s happening around them.

Safeguarding against attacks on soft targets such as airport drop-off lanes, mass transit hubs and athletic stadiums, however, entails sacrifices for each layer of added security, Sweeney said.

“Do you want concrete walls 12 feet tall and a foot-and-a-half thick surrounding every building? Do you want to see barbed wire and concertina wire? Do you want to drive every quarter-mile through a checkpoint and deal with the traffic snarls?” he asked. “The saying is, if we get to that point, then the terrorists have won, and nobody wants to do that.”

Sweeney said the next terror front will likely be in cyberspace, and protecting that could be more effective than physical security barriers.

“Social media is a very powerful tool. A lot of people don't realize how powerful it is,” he said.﻿